The present invention applies to fans and portions thereof. More particularly, the present invention applies to fans at least partially constructed of molded products.
Fans, in one form or another, have been used for thousands of years. A large leap in fan design occurred with the advent of electricity in the early part of the twentieth century. Since that time, fans have continued to evolve, albeit in relatively small and incremental steps. The typical fan, such as an electric fan, includes a motor and a hub about which a plurality of fan blades rotate. The motor can be directly attached to the hub, such as by placing the hub concentrically around the shaft of the motor, and is known as a xe2x80x9cdirect drivexe2x80x9d fan. Alternatively, the hub can be mounted separately from the motor on a pulley with a corresponding pulley mounted to the motor. A drive belt generally is coupled to the pulleys and transfers rotational torque from the motor to the pulley on the hub, and is known as a xe2x80x9cbelt drivenxe2x80x9d fan, which can include a drive belt, chain, gear, and other load transfer elements. In either type, the motor rotates the hub with the fan blades and causes air to be displaced or deflected in a direction away from the blade to create air flow.
Also, since the early part of the twentieth century, fans have been made from metal and wooden components. Typically, a belt driven metallic fan includes two piece hubs where the blades are attached to one piece and a pulley is formed on or attached to a second piece. The first and second pieces of the hub are bolted, welded, or otherwise connected together. In some metallic fans, the blades are stamped from sheets of material and generally have a uniform thickness through a cross-section of the blade. These types of fan blades are termed a xe2x80x9cdeflectorxe2x80x9d type of blade. The fan blade can be welded to the hub, or otherwise attached with rivets, clamps, or screws. In smaller fans, the hub and blades were made as a single piece. However, the stamping process is limited in the depth, length, and angle of the blades, and other practical limitations due to the process. The rotating metal parts of the fan, such as the hub and fan blades, are typically balanced, machined, or otherwise finely tuned to produce high performance fans. High performance fans can produce a relatively large cubic feet per minute (CFM) flow per energy input, such as an electrical watt. Thus, the efficiency can be relatively high on metal fans. However, a high-performance metal fan is generally costly to produce with such efficiency and not suited to general commercial use.
Further developments were made in the evolution of fans with the advent of structural plastics. However, the plastic fans and components, such as hubs and blades, have been relegated to low performance, commercial uses due to design, material, and manufacturing process limitations. The tolerances, molding techniques, and structure generally resulted in a low-cost, low-performance plastic fan. A low-cost, high performance plastic fan eluded those with ordinary skill in the art.
Therefore, there remains a need for a molded plastic fan at relatively low-cost with high-performance capability.
In one embodiment, the present invention provides a high performance molded, substantially non-metallic fan capable of producing at least about 20 cubic feet per minute (xe2x80x9cCFMxe2x80x9d) per input watt at a static pressure of about 0.00 inches of water. In one embodiment, the fan combines a substantially nonmetallic housing, an airfoil cross-sectional fan blade, and a non-metallic hub. The fan blades may be detachable from the hub and rotationally indexable to a variety of pitch angles. Further, the hub and fan blades may include alignment indicia, so that the fan blades can be adjusted to a commensurate pitch relative of other fan blades around the hub.
In another embodiment, the invention provides for a cooler such as an evaporative cooler, comprising a molded cooler housing supported on a base, having an exterior, an interior, and front and rear openings, the base being integrally formed with the housing, at least one brace integrally formed with the housing and capable of supporting at least one evaporative cooling pad positioned within the rear opening of the housing, a molded fan brace coupled to the cooler housing, a molded hub coupled to the fan brace and having a plurality of fan blade receivers, and a plurality of molded fan blades removably attachable to the fan blade receivers, the fan blades each having a blade portion attachable to the fan blade receivers.
In another embodiment, a cooler is provided, comprising a molded cooler housing supported on a base, having an exterior, an interior, and front and rear openings, the base being integrally formed with the housing, at least one brace integrally formed with the housing and capable of supporting at least one evaporative cooling pad positioned within the rear opening of the housing, a molded fan brace coupled to the cooler housing, a molded hub coupled to the fan brace and having a plurality of fan blade receivers, a plurality of molded fan blades removably attachable to the fan blade receivers, the fan blades each having a blade portion attachable to the fan blade receivers on the hub and formed with an airfoil cross section and a longitudinal twist from the blade portion toward a tip end of the fan blades, a first alignment indicia disposed on the fan blade receivers and a second alignment indicia disposed on the fan blades, the cooler having an efficiency rating of at least about 20 CFM of airflow per watt at a static pressure of about 0.00 inches of water.
Further, a molded fan is provided, comprising a molded hub having a plurality of fan blade receivers, and a plurality of molded fan blades coupled to the hub, the fan blades comprising an airfoil cross section having a high pressure portion on one side and a low pressure portion of an opposite side. A fan is also provided, comprising a molded hub having a plurality of fan blade receivers, a plurality of molded fan blades coupled to the fan blade receivers, and a venturi wherein the fan blades are adapted to at least partially rotate within a cross sectional volume formed by the venturi, the fan producing an air flow of at least about 20 CFM of airflow per watt at a static pressure of about 0.00 inches of water.